A manufacturing process of a semiconductor device (semiconductor chip) is roughly divided into a process forming semiconductor circuits, wiring layers, and so on at a front surface side of a semiconductor wafer, and a process cutting (separate into pieces) the semiconductor wafer in accordance with chip shapes. There is a tendency in which the semiconductor wafer is made thinner in accordance with high-performance, high-integration, downsizing and reduction in thickness, and so on of the semiconductor device. When the semiconductor wafer as stated above is processed, a process called a dicing before grinding is applied as a manufacturing process in which the process making a wafer thin and the process separating the chip into pieces are combined (refer to JP-A 2005-343997 (KOKAI) (Reference 1), JP-A 2007-180252 (KOKAI) (Reference 2)).
The dicing before grinding process is performed according to a procedure as stated below. At first, grooves of which depths are shallower than a wafer thickness and deeper than a chip finished thickness are formed at a semiconductor wafer from a front surface side where semiconductor circuits and so on are formed. Next, the semiconductor wafer is grinded from a rear surface side after a protection sheet is attached to the front surface side of the semiconductor wafer. The rear surface grinding of the semiconductor wafer is performed so as to reach the grooves formed from the front surface side. The semiconductor wafer is separated into respective chips by the rear surface grinding of the semiconductor wafer. The semiconductor chip is held by the protection sheet at this stage, and a wafer shape is maintained as a whole.
Next, an adhesive film such as a die-attach film is attached to the rear surface of the semiconductor wafer of which entire shape is maintained by the protection sheet. The adhesive film has an equivalent shape of the semiconductor wafer, and it is cut (separated into pieces) in accordance with respective chip shapes after it is attached to the rear surface of the semiconductor wafer. Accordingly, the adhesive film is attached as a laminated film with a dicing film. The adhesive film is cut by irradiating laser light from a front surface side along a dicing area between the semiconductor chips after the protection sheet is removed.
Array displacement is easy to occur in the semiconductor chips of which wafer shape is maintained as the entire shape when the separated semiconductor chips are transferred to the laminated film with the adhesive film and the dicing film because the dicing film to be laminated with the adhesive film has elasticity. It becomes difficult to cut the adhesive film by a laser process if the array displacement of the semiconductor chips becomes too large or a gap between the semiconductor chips becomes narrow affected by the array displacement. When the array displacement occurs in the semiconductor chips, an irradiation position of the laser light is controlled while checking the positions of the semiconductor chips. However, if the array displacement is large, the number of manufacturing processes increases because an control amount of the laser light increases, or according to circumstances, deterioration of cutting accuracy of the adhesive film and so on are incurred.
A viscous sheet having a rigid base material composed of a polyethylene terephthalate film, a polybutylene terephthalate film, or the like, a vibration relaxation layer arranged at one surface of the rigid base material, and a viscous layer arranged at the other surface of the rigid base material is described in the Reference 1. This viscous sheet is used for the dicing before grinding process of the semiconductor wafer. However, a concrete use application of this viscous sheet is a surface protection sheet when the rear surface of the semiconductor wafer is grinded, and a laminated film in which an adhesive film is laminated with a dicing film is not considered.